We study ice-supersaturation in the cold (< -38∘$<-38^{\circ}$C) arctic troposphere and lower stratosphere using high-resolution quality-controlled radiosonde data. On average, ice supersaturation occurs in about 40 % to 60 % of the profiles with frequency of occurrence increasing with geographic latitude. The frequencies of occurrence show (so far) no long-term trends. The seasonal cycles are not very clear but seem to reverse between more southern to more northern locations. Most profiles with ice-supersaturation have more than one supersaturated layer; this stacking increases as well to the north. Due to the 1‑Hz resolution of the data we find ice-supersaturated layers a few metres thick, but very thick layers extending over almost 5 km are found as well. Median thickness values are smaller than in previous studies, between 100 m and 200 m. The far northern locations display a strong seasonal cycle of the mean layer thickness with maxima in the polar night, probably caused by radiation cooling. Ice supersaturation occurs most frequently directly beneath the tropopause in an upper-tropospheric layer whose depth varies strongly seasonally, being thin in summer and much thicker in winter. Due to the very low temperatures in the Arctic ice supersaturation can occur at the ground. Temperatures in arctic supersaturated layers typically range from −40 to −60 °C, but can occasionally be lower than −70 °C. Water vapour volume mixing ratios range from a few to about 500 ppmv. The relative humidity with respect to ice can exceed 150–160 %. The thickness of supersaturated layers is weakly correlated with its maximum supersaturation, but not with temperature and absolute humidity.

中文翻译：

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关于北极上的冰过饱和

我们使用高分辨率质量控制的探空仪数据研究了北极对流层和低平流层中冷的冰过饱和（<-38∘$ <-38 ^ {\ circ} $ C）。平均而言，冰过饱和发生在大约40％至60％的剖面中，并且出现的频率随着地理纬度的增加而增加。发生频率显示（到目前为止）没有长期趋势。季节周期不是很清楚，但似乎在更南部到更北部的位置之间是相反的。大多数具有冰过饱和的剖面具有不止一个的过饱和层。这种堆积向北也增加。由于数据的1 Hz分辨率，我们发现了几米厚的冰过饱和层，但也发现了延伸近5 km的非常厚的层。中值厚度小于以前的研究，在100 m至200 m之间。极北的位置显示出平均层厚的强烈季节性周期，极夜时有最大值，这可能是由辐射冷却引起的。冰过饱和最常发生在对流层正下方的对流层上层，其深度随季节变化很大，夏季较薄，冬季较厚。由于北极地区的温度非常低，所以地面可能会发生过饱和。北极过饱和层中的温度通常在-40至-60°C的范围内，但有时可能会低于-70°C。水蒸气体积的混合比为几至约500ppmv。关于冰的相对湿度可以超过150–160％。过饱和层的厚度与其最大过饱和度之间存在弱关联，